Cervical Cancer Vaccine: For Women Already Exposed to HPV, Shots May Not Be as Helpful
June 21, 2006
On June 8, the Food and Drug Administration (FDA) approved Merck & Co.'s vaccine Gardasil, which protects against the two HPV strains responsible for 70 percent of all cervical cancers and two strains that cause genital warts. On June 29, the National Advisory Committee on Immunization Practices will meet and is expected to recommend routine vaccination for girls ages 11 and 12.
FDA approved the vaccine for use in females ages 9-26. Because around half of all U.S. teens have sex before age 18 (6 percent before age 13), public health officials say the three-shot series should be administered at a young age. But for sexually active teens and young women who may have already been exposed to HPV, it is less clear whether Gardasil will be of benefit.
Gardasil does not cure HPV, but it may help people who have one strain of the infection from being infected by other strains. A test can determine whether women are infected with HPV, but it cannot specify which strains they have. Hence, HPV-infected women would not know whether Gardasil, which protects against strains 16 and 18, would still be useful.
Also, it is not known how effective Gardasil would be in conferring immunity in women older than 26, as trial data focused on younger women. Merck said it is currently studying the vaccine's efficacy in women up to age 45.
Women should continue to get routine Pap smears, which look for cell changes caused by HPV that can lead to cervical cancer. Even girls who receive Gardasil will likely need regular Pap examinations, said Dr. Mark Wakabayashi, director of gynecologic oncology at City of Hope. "There are still going to be one-third of the HPV strains out there that will cause cervical cancer" and are not blocked by Gardasil, he noted.
Los Angeles Times
06.19.06; Shari Roan
This article was provided by CDC National Prevention Information Network. It is a part of the publication CDC HIV/Hepatitis/STD/TB Prevention News Update.